Currently, numerous chemicals are being used to treat various types of cancers and such treatment is termed as chemotherapy. Chemotherapy is associated with adverse side effects, such as hair loss, diarrhea, skin rash etc. simply because the chemicals used to kill cancer cells also affect normal cells adversely. Chemotherapy requires different chemical drugs to treat different types of cancers.
In our U.S. Pat. No. 5,565,431, the disclosure of which is incorporated herein by reference, cancer cell inhibitors Atroporin (AT) and Kaotree (KT) were isolated by fractionating venoms of Crotalus atrox and Naja kaouthia snakes respectively by high pressure liquid chromatography (HPLC). Atroporin (AT) had a molecular weight of approximately 35,000 Daltons, whereas Kaotree (KT) had a molecular weight of approximately 6,000 Daltons. The homogeneous preparation of AT and KT showed killing effects on several types of human (breast, colon, liver, ovary etc.) and animal cancer cells in concentration as low as 0.5 μg/ml, and having no effect on normal mouse kidney, liver and spleen cells as high as 5.0 μg/ml. Both Atroporin and Kaotree exhibited the property of preventing the formation and regression of ascitic tumors caused by myeloma cells in Balb/c mice. The combination of AT and KT showed elevated anticancer activity in both in vitro and in vivo systems.
The relatively large molecular sizes of intact AT and KT limit the routes by which they can be administered.
The relatively large molecular sizes of AT and KT also raises the possibility of patient adverse reactions.
The fact that AT and KT are derived from venoms further makes gaining commercial acceptance more difficult.
Smaller molecules which mimic the properties of AT and KT and are not derived from venom would be very desirable.